# in r programming #

1) Create an object of S3 class cow containing :

An identification Number for the cow

The cow breed

A dataframe of the cow age (months), milk yield in first lactation (kg), milk yield in second lactation (kg)

2) Create a:

summary() method reporting mean and SD for the lactations of the cow

print() method reporting cow, cow breed, and age in months

3) Repeat 1) and 2) but creating an S4 class

4) Create an S4 class called cowM which inherits the S4 cow class and contains a dataframe with

mastitis in first lactation (presence absence)

mastitis in second lactation (presence absence)